Overview

Chlamydia is 1 of the most common sexually transmitted infections (STIs) in the UK.

It's passed on through unprotected sex (sex without a condom) and is particularly common in sexually active teenagers and young adults.

Symptoms of chlamydia

Most people with chlamydia do not notice any symptoms and do not know they have it.

If you do develop symptoms, you may experience:

• pain when peeing
• unusual discharge from the vagina, penis or bottom
• in women, pain in the tummy, bleeding after sex and bleeding between periods
• in men, pain and swelling in the testicles

If you think you're at risk of having a sexually transmitted infection (STI) or have any symptoms of chlamydia, visit a GP, community contraceptive service or local genitourinary medicine (GUM) clinic to get tested.

How do you get chlamydia?

Chlamydia is a bacterial infection. The bacteria are usually spread through sex or contact with infected genital fluids (semen or vaginal fluid).

You can get chlamydia through:

• unprotected vaginal, anal or oral sex
• sharing sex toys that are not washed or covered with a new condom each time they're used
• your genitals coming into contact with your partner's genitals – this means you can get chlamydia from someone even if there's no penetration, orgasm or ejaculation
• infected semen or vaginal fluid getting into your eye

It can also be passed by a pregnant woman to her baby.

Chlamydia cannot be passed on through casual contact, such as kissing and hugging, or from sharing baths, towels, swimming pools, toilet seats or cutlery.

Is chlamydia serious?

Although chlamydia does not usually cause any symptoms and can normally be treated with a short course of antibiotics, it can be serious if it's not treated early on.

If left untreated, the infection can spread to other parts of your body and lead to long-term health problems, especially in women.

In women, untreated chlamydia can cause pelvic inflammatory disease (PID), ectopic pregnancy and infertility.

In men, in rare cases, chlamydia can spread to the testicles and epididymis (tubes that carry sperm from the testicles), causing them to become painful and swollen. This is known as epididymitis or epididymo-orchitis (inflammation of the testicles).

It can also sometimes cause reactive arthritis in men and women.

This is why it's important to get tested and treated as soon as possible if you think you might have chlamydia.

Getting tested for chlamydia

Testing for chlamydia is done with a urine test or a swab test.

You do not always need a physical examination by a nurse or doctor.

Anyone can get a free and confidential chlamydia test at a sexual health clinic, a genitourinary medicine (GUM) clinic or a GP surgery.

You can also buy chlamydia testing kits to do at home.

How chlamydia is treated

Chlamydia can usually be treated easily with antibiotics.

You may be given a course of doxycycline to take for a week or azithromycin to take once a day for 3 days.

If you have doxycycline, you should not have sex (including oral sex) until you and your current sexual partner have finished treatment.

If you have azithromycin, you should wait 7 days after treatment before having sex (including oral sex).

It's important that your current sexual partner and any other recent sexual partners you have had are also tested and treated to help stop the spread of the infection.

Under-25s who have chlamydia should be offered another test 3 to 6 months after being treated.

This is because young adults who test positive for chlamydia are at increased risk of catching it again.

Sexual health or genitourinary medicine (GUM) clinics can help you contact your sexual partners.

Either you or the clinic can speak to them, or they can be sent a note advising them to get tested.

The note will not have your name on it, so your confidentiality will be protected.

Preventing chlamydia

Anyone who's sexually active can catch chlamydia.

You're most at risk if you have a new sexual partner or do not use a barrier method of contraception, such as a condom, when having sex.

You can help to prevent the spread of chlamydia by:

• using a condom every time you have vaginal or anal sex
• using a condom to cover the penis during oral sex
• using a dam (a piece of thin, soft plastic or latex) to cover the female genitals during oral sex or when rubbing female genitals together
• not sharing sex toys

If you do share sex toys, wash them or cover them with a new condom between each person who uses them.

Symptoms

Most people who have chlamydia don't notice any symptoms.

If you do get symptoms, these usually appear between 1 and 3 weeks after having unprotected sex with an infected person. For some people they don't develop until many months later.

Sometimes the symptoms can disappear after a few days. Even if the symptoms disappear you may still have the infection and be able to pass it on.

Symptoms in women

At least 70% of women with chlamydia don't notice any symptoms. If they do get symptoms, the most common include: 

• pain when urinating
• unusual vaginal discharge
• pain in the tummy or pelvis
• pain during sex
• bleeding after sex
• bleeding between periods

If chlamydia is left untreated, it can spread to the womb and cause a serious condition called pelvic inflammatory disease (PID). This is a major cause of ectopic pregnancy and infertility in women.

Symptoms in men

At least half of all men with chlamydia don't notice any symptoms. If they do get symptoms, the most common include: 

• pain when urinating
• white, cloudy or watery discharge from the tip of the penis 
• burning or itching in the urethra (the tube that carries urine out of the body)
• pain in the testicles

If chlamydia is left untreated, the infection can cause swelling in the epididymis (the tubes that carry sperm from the testicles) and the testicles. This could affect your fertility.

Chlamydia in the rectum, throat or eyes

Chlamydia can also infect:

• the rectum (back passage) if you have unprotected anal sex – this can cause discomfort and discharge from your rectum
• the throat if you have unprotected oral sex – this is uncommon and usually causes no symptoms
• the eyes if they come into contact with infected semen or vaginal fluid – this can cause eye redness, pain and discharge (conjunctivitis)

When to seek medical advice

If you have any symptoms of chlamydia, visit your GP, community contraceptive service or local sexual health clinic as soon as possible.

Find a sexual health service near you.

You should also get tested if you don't have any symptoms but are concerned you could have a sexually transmitted infection (STI).

If you're sexually active and under 25 years old, you should get tested for chlamydia every year or every time you have a new partner.

Diagnosis

The only way to find out if you have chlamydia is to get tested. You can get tested whether or not you have symptoms.

What does the chlamydia test involve?

The recommended tests for chlamydia are simple, painless and generally very reliable.

They involve sending a sample of cells to a laboratory for analysis. You don't necessarily have to be examined by a doctor or nurse first and can often collect the sample yourself.

There are 2 main ways the sample can be collected:

• using a swab – a small cotton bud is gently wiped over the area that might be infected, such as inside the vagina or inside the anus
• urinating into a container – this should ideally be done at least 1 hour after you last urinated

Men will usually be asked to provide a urine sample, while women will usually be asked to either swab inside their vagina or provide a urine sample.

The results will normally be available in 7 to 10 days. If there's a high chance you have chlamydia – for example, you have symptoms of the infection or your partner has been diagnosed with it and you've had unprotected sex with them – you might start treatment before you get your results.

When should I get tested?

Don't delay getting tested if you think you might have chlamydia. Being diagnosed and treated as soon as possible will reduce your risk of developing any serious complications of chlamydia.

You can get a chlamydia test at any time – although you might be advised to repeat the test later on if you have it less than 2 weeks since you had sex because the infection might not always be found in the early stages.

You should consider getting tested for chlamydia if:

• you or your partner have any symptoms of chlamydia
• you've had unprotected sex with a new partner
• a condom splits while you're having sex
• you or your partner have had unprotected sex with other people
• you think you could have a sexually transmitted infection (STI)
• a sexual partner tells you they have an STI
• you're pregnant or planning a pregnancy

If you're under 25 years of age and sexually active, getting tested every year or when you change sexual partner is recommended.

If you have chlamydia, you may be offered another test around 3 to 6 months after being treated. This is because young adults who test positive for chlamydia are at increased risk of catching it again.

Where can I get a chlamydia test?

You can get a free, confidential chlamydia test at:

• a sexual health clinic
• a genitourinary medicine (GUM) clinic
• your GP surgery
• most contraceptive clinics

You can go to whichever place is the most comfortable and convenient for you. 

Find your nearest sexual health clinic

You can also buy chlamydia testing kits to do at home.

Treatment

Complications

If chlamydia isn't treated, it can sometimes spread and cause potentially serious problems.

Complications in women

Pelvic inflammatory disease (PID)

In women, chlamydia can spread to the womb, ovaries or fallopian tubes. This can cause a condition called pelvic inflammatory disease (PID).

PID can cause a number of serious problems, such as:

• difficulty getting pregnant or infertility
• persistent (chronic) pelvic pain
• an increased risk of ectopic pregnancy (where a fertilised egg implants itself outside the womb)

The symptoms of PID are generally similar to the symptoms of chlamydia, including discomfort or pain during sex, pain during urination, and bleeding between periods and after sex.

PID is usually treated with a 2-week course of antibiotics. The risk of experiencing problems such as infertility is lower if it's treated early, so it's important to seek medical advice as soon as possible if you have symptoms of the condition.

Pregnancy complications

If you have chlamydia that's not treated while you're pregnant, there's a chance you could pass the infection on to your baby. If this happens, your baby may develop an eye infection (conjunctivitis) and lung infection (pneumonia).

If your baby has symptoms of these conditions, your midwife or GP can arrange for a test to check for chlamydia, and antibiotics can be used to treat the infection.

Untreated chlamydia in pregnancy may also increase the risk of problems such as premature labour and birth (before 37 weeks of pregnancy) or with a low birthweight.

Complications in men

Inflammation of the testicles

In men, chlamydia can spread to the testicles and epididymis (tubes that carry sperm from the testicles), causing them to become painful and swollen. This is known as epididymitis or epididymo-orchitis. This is very rare.

The inflammation is usually treated with antibiotics. If it's not treated, there's a possibility it could affect your fertility.

Reactive arthritis

Chlamydia is the most common cause of sexually acquired reactive arthritis (SARA). This is where your joints, eyes or urethra (the tube that passes urine out of the body) become inflamed, usually within the first few weeks after having chlamydia.

It can affect women who have had chlamydia but is more common in men.

There's currently no cure for SARA, but most people get better in a few months. In the meantime, treatment with non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can help relieve the symptoms.